Unsure how to change VM options from config.hdf

[hydrogen18]

Out of the box, HipHop VM wants 1.2 gigabytes of memory. This options are controlled by

./hphp/runtime/base/runtime-option.cpp:408:size_t RuntimeOption::VMTranslAHotSize   =   4 << 20;
./hphp/runtime/base/runtime-option.cpp:409:size_t RuntimeOption::VMTranslASize      = 32 << 20;
./hphp/runtime/base/runtime-option.cpp:410:size_t RuntimeOption::VMTranslAProfSize  = 32 << 20;
./hphp/runtime/base/runtime-option.cpp:411:size_t RuntimeOption::VMTranslAStubsSize = 32 << 20;
./hphp/runtime/base/runtime-option.cpp:412:size_t RuntimeOption::VMTranslGDataSize  = RuntimeOption::VMTranslASize >> 2;

As you can see I adjusted the values down to 32 megabytes and got HipHop VM to run on a minimal virtual machine. These values are in the RuntimeOption namespace, but I am not sure how to set them from config.hdf. Can someone document how to do this and what the impact of adjusting each value is?

[scannell]

Duplicate of #1129, we're talking about this there. b5163ad should tell you though. These are various JIT parameters -- sizes of translation structures where compiled code is cached. The defaults are what we tune for. It should work with these smaller but we have done no internal performance testing on minimal sizes.

[hydrogen18]

Thanks.